variation

Question 1

variation definition

Answer 1

the differences in characteristics between organisms

Question 2

interspecific variation

Answer 2

variation between members of different species

Question 3

intraspecific variation

Answer 3

differences between organisms within a species

Question 4

2 main causes of variation

Answer 4

• genetic material
• organism’s living environment

Question 5

genetic causes of variation

Answer 5

• alleles (genes have different alleles. A gene for a particular characterisitc has alleles producing different effects)
• mutations (changes to DNA sequence/genes leads to change of proteins which changes physical/metabolic characteristics
• meiosis (genetic material of mother and father mixes up to produce varied gametes)
• sexual reproduction (offspring inherits genes from parents so each individual differs)
• chance (when 2 gametes combine)

Question 6

discontinuous variation

Answer 6

when there are 2 or more distinct categories
e.g. blood group, plant colour/seed shape, antibiotic resistance

Question 7

continuous variation

Answer 7

where the individuals in a population vary within a range
e.g. height, mass, milk yield, leaves SA, width and length of microorganisms

Question 8

environmental causes of variation

Answer 8

• climate
• food
• lifestyle
  e.g. accents, piercings

Question 9

both genetic and environmental causes of variation examples

Answer 9

e.g.
- height (diet)
- flagellum (genes determine if it grows flagellum, but some will only grow them in certain environments)

Question 10

how to represent discontinuous variation

Answer 10

• bar chart
• pie chart

Question 11

how to represent continuous variation

Answer 11

• frequency table
• plotted onto histogram

Question 12

normal distribution

Answer 12

• symmetrical bell shaped curve
• same mean, mode, median

Question 13

standard deviation

Answer 13

measure of how spread out the data is

Question 14

how to calculate standard deviation

Answer 14

√((∑ ( X − X ¯ ) ^2)/ n − 1)

Question 15

Student’s t test

Answer 15

used to compare the mean values of the 2 sets of data